Nitrogen toxicity in doubt

It wonders me why the leaves drop down few hours before night time. Most of the time of light period they look OK and then they drop. Why is that? Never had this problem before.

droopy look doesnt come from overwatering,since you are in coco already. plants with weaker stems respond to being bent like this.not N toxicity.nothing to worry about.they look good.you might just give some time between training sessions.flush not needed.up to you of course but I wouldn't flush them.unnecessary flushing would make more deficiency-like signs and confuse the grower.

Also, temp 26C and 50-60% RH. Since I swapped tents and before flipping them to flowering I got this. Using flora series, last 3 days I did some adjustments I got rid of calmag and feed plants day after day for 3 days with 1/3 of nutrient strength. Aiming to bang down ppm and nitrogent.

It looks to me like a combination of overwatering and over feeding! Let her dry out good and give her a good flush with only ph balance water! This should get her together for you ! Good luck 👍🍀